Floppy flying toy

ABSTRACT

A hand-thrown flying device that is flexible and “compressible,” yet which regains a substantially planar shape for flight. The device may include a flexible airfoil and be configured for air passage between a top and bottom surface. The airfoil may define a central opening and/or a plurality of other macroscopic openings. The airfoil may include non-air porous and/or air porous material. A rim, annular or otherwise shaped, may be coupled to the airfoil. This rim may be non-tensed.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10/068,701, filed Feb. 4, 2002, entitled Floppy Flying Ring Toy and having the same inventor as above. application Ser. No. 10/068,701 claims the benefit of U.S. Provisional Application No. 60/266,032, filed Feb. 2, 2001, entitled Flexible Flying Ring Toy and having the same inventor as above.

FIELD OF THE INVENTION

[0002] The present invention relates to hand thrown flying devices and, more specifically, hand thrown flying ring and disc toys.

BACKGROUND AND SUMMARY OF THE INVENTION

[0003] A lightweight, flat disk or ring will roll significantly to one side when thrown with a spin. This is caused by lift forces forward of the center of gravity interacting with the object's angular momentum that imparts a torque on the object that results in the device rolling in flight. If a spinning flying disc or ring is aerodynamically balanced, the angular momentum provides flight stability much like a gyroscope. Flying discs and rings such as Frisbees™, Aerobies™ (U.S. Pat. Nos. 4,560,358 and 4,456,265) and Woosh™ (U.S. Pat. No. 4,944,707, and invented by the inventor herein) use different approaches to achieve aerodynamic stability, especially roll stability.

[0004] The Frisbee is a saucer-shaped device that can be thrown over relatively long distances. A player throws such a disc by grasping its edge and flexing the wrist, while holding the forearm in a neutral position. Next, the player extends the wrist and releases the disc, i.e. the player “flings” from the wrist, imparting spin to the disc, resulting in it being propelled through the air with gyroscopic stability. Such a disc will fly over relatively long distances without rolling because of its relatively high mass, peripheral mass distribution, solid/rigid construction and domed aerodynamic structure.

[0005] The Aerobie has a relatively large mass, but, unlike the Frisbee, it has a mass that is distributed peripherally about a central void. It also has a special, diamond-shaped airfoil, offering roll stable flight characteristics over a wide range of speeds. The Aerobie has set distance records for a flying toy. The Aerobie goes very fast, is quite thin, and has a rigid internal frame that makes it an intimidating object to catch and can readily cause harm to a person or damage to property.

[0006] Rigid flying discs and flying rings have the disadvantage of damaging objects and hurting users when caught. They are also disadvantageous in that they are not “compressible” or “crumplable” so as to be placed in a pocket or otherwise easily transported.

[0007] Woosh is a semi-rigid, resilient, ring-like flying toy. It is relatively lightweight including light-weight outer and inner, ring-like boundary structures defining an annular space that is spanned by an airflow permeable airfoil web joined to and tensed between the outer and inner boundary structures. This “leaky airfoil” contains microscopic openings (in the order of 0.01″) and is the basis for the Woosh Ring's non-rolling flight characteristics over a wide range of relatively slow speeds. Besides being lightweight and only semi-rigid, a benefit of the Woosh Ring over a Frisbee is that it is relatively thin and flat for increased ease in transporting. A disadvantage of Woosh is the need to use expensive fabrics such as spandex to achieve a wrinkle-free, tensed web. Another disadvantage is that although the Woosh can be twisted and then folded to a reduced size, this size is normally too large for a normal pocket and the frame of Woosh can become permanently warped or may even crack apart due to this twisting and folding. Yet another disadvantage of the Woosh is that due to its highly tensed structure it is more likely to bounce out of a hand before being grasped making it difficult to catch. In addition, when exposed to water, for example when used at a pool, a Woosh absorbs water in the microscopic openings of the airfoil causing it to become quite heavy and to roll during flight.

[0008] Other prior art flying toys include the Floppy Disc, (U.S. Pat. No. 5,078,637), the Flippy Flier (U.S. Pat. No. 4,223,473) and the Winger™. The Floppy Disc and the Flippy Flier are limp, domed-shaped flying discs. The Winger™ is a limp, domed, heavy flying ring without a porous airfoil member. These devices are characterized in that they are relatively heavy and do not roll significantly in flight because their aerodynamic forces are small compared to their inertia. They are disadvantageous, amongst other reasons, in that they have high wing loading, high drag and are bulky which may render them hard to catch, limits their flight distance, and makes them difficult to fit in one's pocket.

SUMMARY OF THE INVENTION

[0009] Thus, in an effort to overcome the shortcomings of the prior art, the present invention is directed towards providing an improved flying device that may exhibit relatively low wing loading and drag, good flight stability, and that is easy to catch and fits easily in one's pocket without causing the device to be permanently damaged.

[0010] In one aspect, the present invention includes a non-tensed outer rim and a flexible airfoil that is substantially planar in flight and has a plurality of air passage openings.

[0011] In another aspect, the present invention includes a flexible airfoil that is substantially planar in flight and configured to be folded over and compressed in three mutually orthogonal directions, yet capable of being readily unfolded to regain a substantially planar shape.

[0012] In yet another aspect, the present invention includes a flexible airfoil that is substantially planar in flight and has a plurality of macroscopic air passage openings.

[0013] And in yet another aspect, the present invention includes a flexible airfoil that is substantially planar in flight, has a plurality of air passage openings and includes substantially non-air porous material. Other aspects of the present invention are discussed herein.

[0014] The attainment of the foregoing and related aspects, advantages and features of the present invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIGS. 1-3 are a plan view, a first cross-sectional and a second cross-sectional views of a floppy flying toy in accordance with the present invention.

[0016]FIG. 4 is a plan view of another floppy flying toy in accordance with the present invention.

[0017]FIG. 5 is a view of another floppy flying toy in accordance with the present invention.

[0018]FIGS. 6 and 7A-7D are a plan view and cross-sectional views of another floppy flying toy in accordance with the present invention.

[0019] FIGS. 8-13 are views of other embodiments of a floppy flying toy in accordance with the present invention.

[0020]FIG. 14 is a view of a woven or crocheted floppy flying toy in accordance with the present invention.

DETAILED DESCRIPTION

[0021] The term “airfoil structure” as used herein generally refers to a structure that presents to an air stream (i.e., in flight) a differential path over the upper and lower surfaces of the structure to achieve lift, various airfoil structures are known in the art.

[0022] The term “crumpleable” as used herein generally refers to a material or structure that compresses in three mutually orthogonal directions when acted on by suitable compressive forces yet that is capable of recovering a pre-crumpled shape in the absence of the compressive force and in the presence of a decompressive force such as centrifugal force or other.

[0023] Referring to FIGS. 1-3, plan, first cross-sectional and second cross-sectional views of a floppy flying device 10 in accordance with the present invention are respectively shown. The flying device 10 is substantially planar (particularly in flight) and may include a substantially annular outer rim 12 and an airfoil 14. Note that rim 12 or the like need not be annular. The airfoil, in the embodiment of FIGS. 1-3, extends substantially inwardly from the outer rim and may be configured to define a plurality of air passage openings.

[0024] The air passage openings may include a central opening 15 bounded, at least in part, by an inner rim 11 and a plurality of smaller openings 18 provided in the airfoil between the outer and inner rims. The central opening 15 allows air to flow freely without a pressure differential in the center of the device. The peripherally disposed openings 18 occupy approximately ⅓ of the surface area defined by inner rim 11 and outer rim 12. Note that airfoil 14 may be formed of substantially non-air porous material and openings 18 may be “macroscopic” in size (in the order of 0.1″ or greater).

[0025] Device 10 as illustrated in FIGS. 1-3 has three series of three progressively sized openings. The relative size of the central opening, peripheral openings and the airfoil provide desired lift and flight stability as discussed elsewhere herein. It should be recognized that while FIGS. 1-3 illustrate one arrangement of airfoil 14 and air passage openings 15, 18, these components may be otherwise arranged or configured without departing from the present invention (for example, see FIG. 4).

[0026] Device 10 may be fabricated in different ways. In one embodiment, device 10 may be formed of a molded plastic or rubber substance. Suitable material includes an elastomeric plastic, such as polyurethane, or other materials. Suitable polyurethane include ester polyurethane with shore hardnesses from the high 80s to 95A or other. Shore hardness of 90A to approximately 92-93A may provide a desired tradeoff between softness for easy catching or damage reduction and sufficient stiffness for flight. Polyurethane and like materials are also desirable in that they may be recycled. It should also be. recognized that polyurethane (and like material) is substantially non-air porous and thus tends not to absorb water when exposed to it, in contrast to stretched fabric (and like material) that is substantially air porous. Flying toys with airfoils made of air porous materials, particularly stretched air porous material, have significantly diminished flight capacity due to the added water weight and clogged air passage openings, thus making them disadvantageous for use around pools and other water sources.

[0027] In flight, device 10 achieves a substantially planar shape. If device 10 is folded prior to flight, it is preferably unfolded and positioned in a relatively planar shape before flight is attempted. When not in flight, device 10 may be flopped and/or folded onto itself, or otherwise positioned. For example, device 10 could be compressed by human hand into a collection of lobes and folded over portions that resemble a ball-like shape or mass. A user may easily place this “ball” in his or her pocket or bag, etc. For use, the device is taken out, unfolded to a planar or near planar shape, held by the outer rim and then flung forward with a flick of the wrist.

[0028]FIG. 2 illustrates a cross-sectional view from line 2-2′ of FIG. 1 and FIG. 3 illustrates a cross-sectional view from line 3-3′ of FIG. 1. While device 10 may be made of any suitable dimensions, in one embodiment it may have the following representative dimensions. The outer rim may have a diameter of approximately 10″, and the inner rim (while not necessarily round) may have an average diameter of approximately 6″. Outer rim 12 may have a diameter of approximately 0.16″, the airfoil may have a thickness of approximately 0.040″ and the inner rim may have a diameter of 0.080″.

[0029] While device 10 may be provided without a relatively pronounced inner rim 11, inner rim reduces tears emanating from the central opening. Note the inner rim and the rims around openings 18 also serve to reduce stretching that may cause device 10 to deviate from a substantially planar configuration, thereby deleteriously affecting flight. The relatively greater thickness and weight of outer rim 12 provides ballast to device 10, and the provision of this is ballast far from the center of the device contributes significantly to its angular momentum and hence flight stability.

[0030]FIG. 3, from the left, illustrates a portion of airfoil 14 which terminates in a first rim section 13 of an airfoil air-passage opening 18. Rim 13 may have a diameter of 0.080″. Opposite first rim section 13 is a second rim section 17 that may have the same height or diameter as section 13, but be more tapered in lateral cross-section. A third rim section 9, that may be similar to section 13, is coupled by airfoil 14 to section rim section 17. Note that these dimensions are representative.

[0031] Please note also that the top and bottom of device 10 are interchangeable, or in other words, the device may be thrown with either side up, eliminating confusion and “user-error” amongst users.

[0032] Referring to FIG. 4, a plan view of another floppy flying device 10A in accordance with the present invention is shown. Device 10A is similar to device 10 of FIG. 1, yet central opening 15A is filled in part by airfoil material 7A to create a “spider-web” or “steering wheel” like appearance. To maintain approximately the same (or similar) amount of air passage area within outer rim 12A, the number and/or size of the peripheral openings 18A is increased or the average diameter of inner rim 11A may be increased, etc.

[0033]FIG. 5 illustrates another floppy flying device 20 in accordance with the present invention. Device 20 includes an annular rim 22, and an airfoil 24 which defines a central opening 25 and a plurality of smaller holes 28. Device 20 may be made in a manner similar to device 10 of FIGS. 1-4, yet with different sized and a different number of smaller openings in the airfoil. Device 20 preferably obtains a substantially planar shape in flight, though it is shown partially folded or “flopped” over in FIG. 5.

[0034] Referring to FIG. 6, a plan view of another flying device 30 in accordance with the present invention is shown. The flying ring 30 includes an annular rim 32 that is preferably made of a flexible material that provides ballast to the ring and facilitates gripping by a user's hand. The rim may comprise a rope, cord, tube or filament or like material, or be formed of a molded material or otherwise configured. Cross-sectional views of various exemplary annular rim arrangements are shown in FIGS. 7A-7D. Device 30 and the other flying devices herein are crumpleable.

[0035] An airfoil 34 is preferably coupled to annular rim 32. In FIG. 6, this is achieved by mounting members or “grips” 333 that are provided over rim 32 and affixed to airfoil 34. Airfoil 34 is preferably made of a material that is lightweight and flexible. Preferred characteristics for the embodiment of FIG. 6 include that the material neither appreciably wrinkles nor stretches out. Preferred materials include urethane, dacron/mylar, vinyl/mylar or other materials with similar properties.

[0036] Grips 33 may be made of neoprene, dacron/mylar, cloth, nylon, molded plastic or any other suitable material. Desirable characteristics include that the material is generally resistant to abrasion, easy to grip and flexible. Grips 33 may be stitched, glued or otherwise fastened to airfoil 34. Note that while three grips are shown in FIG. 6, other grip arrangements are possible including a greater plurality of grips and a singular grip that covers the length of the annular rim (for example, as shown in FIGS. 8-11).

[0037] Airfoil 34 is preferably configured and arranged within annular rim 32 so as to include holes or openings that permit air passage. These air passages reduce lift, and since lift interacts with angular momentum to produce a torque that induces rolling, reducing lift in this manner reduces rolling. FIG. 6 illustrates an airfoil embodiment with a central opening 35 and a plurality of smaller openings 38. The smaller openings include those formed in the airfoil material and those defined by the edge of the airfoil material and the annular rim 32. Note that central opening, shown non-circular, may be circular or non-circular.

[0038] FIGS. 7A-7D illustrate cross-sectional views of a plurality of annular rims in accordance with the present invention. FIGS. 7A-7B are taken along the line indicated in FIG. 6, FIG. 7C is taken along the line indicated in FIG. 5, and FIG. 3D is taken along the line indicated in FIG. 8 (below).

[0039] FIGS. 7A-7B illustrate annular rim 32 implemented with a solid or hollow internal member 46, 47, respectively. That member may be a solid or hollow rope or other flexible filament and grip 30 is mounted around member 46, 47 and secured to airfoil 34 via stitches 8 or glue or other suitable fastener. Member 46, 47 may be made of a braided nylon rope, extruded vinyl tubing or another suitable material. FIG. 3C illustrated a solid integrally formed annular rim member of the type formed in the embodiment of FIGS. 1-5. FIG. 3D is discussed below with reference to FIGS. 8-11.

[0040]FIGS. 8 and 9 illustrate another embodiment of a floppy flying ring in accordance with the present invention. FIG. 8 shows ring 60 in a substantially planar arrangement, while FIG. 9 shows the same ring in a crumpled arrangement. FIGS. 10 and 11 illustrate another embodiment of a floppy flying ring in accordance with the present invention. FIG. 10 shows ring 70 in a substantially planar arrangement, while FIG. 11 shows the same ring folded approximately in half. FIG. 9 illustrates well the “crumpleable” nature of a floppy flying device in accordance with the present invention. The device of FIG. 9 recovers the planar shape of FIG. 8 when a user grabs rim 62 and throws the device moving their arm laterally and flicking their wrist upon release.

[0041] Each of rings 60, 70 includes an annular rim 62, 72 and an airfoil 64, 74. The airfoils each define a central opening 65, 75 and have a plurality of holes 68, 78 for air passage in flight. FIGS. 8-11 illustrate a mounting member 66, 76 formed of a seam-biased tape or neoprene or the like that is provided at rim 62, 72 and fastened to the airfoil. In contrast to the plurality of grips of FIG. 1, member 66, 76 is substantially continuous.

[0042]FIG. 7D illustrates the mounting of member 66, 76 to an airfoil 64, 74. A tube or rope or the like 18 is preferably provided within member 66, 76 which can be mounted to the airfoil by stitches 19 or glue or other means. Note that members 46, 47, 22, 49 (and weights 53 of device 50 of FIG. 14) represent elements that provide ballast to the outer rim and they are exemplary. Thus, they may in some instances be substituted for one another, or a different structure, providing a ballast function, can be utilized.

[0043] FIGS. 12-13 illustrate two additional embodiments of a floppy flying ring in accordance with the present invention. FIG. 12 illustrates a ring 80 that includes an annular rim 82 (substantially as described above for rim 12 or 62 or other) and an airfoil 84 that defines a central opening 85. In contrast to the urethane, mylar or other relatively non-air permeable materials discussed above, airfoil 84 is formed of a substantially air-porous material, i.e., a material having a relatively large plurality of smaller holes. Representative materials include spandex, treco, etc. This material tends to be limp and flexible. To facilitate a planar shape in flight, a rubber band or similar elastic member 83 (actually not visible) is provided interior of the airfoil material at the inner rim 81 of airfoil 84 to constrict opening 85 and tense the airfoil such that it more readily achieves a substantially planar shape during flight.

[0044] The ring 90 of FIG. 13 is similar to that of FIG. 12 and has an annular rim 92 and an airfoil 94. A difference in ring 90 is that a central opening is not provided. To compensate for the lack of a central opening the porosity of the material used for airfoil 94 is significantly increased over that used in airfoil 84. Various woven fabrics may suffice. Alternatively, airfoil 94 could be configured with a plurality of holes such as holes 28, 48, 68, 78, etc., that are distributed across the airfoil and compensate for lack of a central opening. This latter arrangement may be configured with either a generally air-porous airfoil material (e.g., a woven material) or a generally non-air porous material (e.g., urethane, etc.), though the air passage openings would have to be adjusted in size to achieve the desired lift reduction to reduce or eliminate roll.

[0045]FIG. 14 illustrates another embodiment of a floppy flying device 50 in accordance with the present invention. Device 50 is preferably formed by crochet or is related knitting or weaving techniques. The ring includes an annular rim 52 that includes thread or yarn which joins a plurality of weights, 53 provided in a relatively distributed manner about the periphery of the ring. These weights provide ballast and serve a function similar to the annular rims portrayed in FIGS. 7A-7D. The weights 53 may be made of wood or plastic or another suitable material. The airfoil 54 is preferably formed of yarn or other material, which may be cotton, wool, synthetic or other, and configured to define a central opening 55 and a relatively large plurality of much smaller holes 58. These smaller holes are effectively the spaces between crochet knots. The crochet work is preferably started on the inner rim and progresses to the outer rim (rim 52). The outer rim region may have a slight up-and-down wave relative to the inner rim region when placed on a flat surface, but this wave will flatten out when the device is thrown due to centrifugal forces exerted on the ring.

[0046] The number of knots per concentric knot circle has to increase as the airfoil expands outwardly. The number of knots per circle and their spacing will vary depending on the initial diameter of the ring, but the requisite increase to maintain a flat ring is within know crocheting practices. The size of openings 55 and 58 is preferably analogous to size of the other air passage openings discussed herein. In one embodiment, the ring of FIG. 14 has an inner diameter of approximately 5.5″ and an outer diameter of 8.5″.

[0047] With respect to general considerations for operation and design of a floppy flying device in accordance with the present invention the following is provided. For a “ring” embodiment in flight, a cross-section along the flight path provides two airfoils, a front one and a rear one. The front airfoil interacts with the airflow first. The front airfoil generates lift due to its angle of attack and the relatively high airflow over the front airfoil rather than under it. The rear airfoil meets the downwash from the front airfoil and generate less lift because of the relatively lower angle of attack relative to the air stream it encounters. With a porous airfoil, the front airfoil generates only a small amount of lift and the rear airfoil, encounters a negligible amount of downwash, and thus has about the same lift vector. The forces balance out over a wide speed range. The porous floppy flying device of the present invention, with appropriate inner and outer diameters, ratios of holes to airfoil surface, and thickness (i.e., height) of annular rim, flies straight and true without rolling from when it is released at a high launch speed until it lands.

[0048] In the embodiments illustrated in FIGS. 5-6 the outer diameters are approximately 11″ and the inner diameters are 6″. For the embodiments of FIGS. 1-6, more than approximately 15-20% of the surface area defined by the inner and outer rims may be given to air passage holes and more preferably approximately 30-40%, for example approximately ⅓, of this surface area may be given to air passage holes. The dimensions for the flying devices of FIGS. 8-12 may be similar to those of FIGS. 1-6, though flying devices size may vary widely. Proportionality is preferably maintained.

[0049] It should be recognized that the embodiments disclosed herein may be made of different materials and different sizes. By way of example, device 10 of FIGS. 1-3 could made of a foam based material (e.g., thermoforming foam ranging from that used in “boogie boards” to that used in Nerf® footballs, etc.) and of appropriately larger thickness dimensions to increase durability and provided desired ballast and flotation. It is contemplated that this or other flying toys and disks may also be made larger in overall length, for example, having 3′ and 4′ diameters.

[0050] While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims. 

1. A hand-thrown flying device, comprising: an outer rim; and a flexible airfoil disposed at least in part within said rim and capable of having a substantially planar shape, said airfoil configured to permit air passage; wherein said rim and airfoil are configured to be folded over and compressible in three mutually orthogonal directions, yet capable of being readily unfolded to regain a substantially planar shape.
 2. The device of claim 1, wherein said airfoil defines a plurality of macroscopic air passage openings.
 3. The device of claim 1, wherein said airfoil defines a central opening.
 4. The device of claim 3, wherein said airfoil includes a peripheral band disposed about said central opening and wherein approximately ¼ to ½ of an inner rim of said band and said outer rim is given to said air passage openings.
 5. The device of claim 3, wherein said airfoil includes a peripheral band disposed about said central opening and said peripheral band is configured to define a plurality of peripherally disposed macroscopic air passage openings.
 6. The device of claim 2, wherein said air passage openings are of at least two different sizes.
 7. The device of claim 1, wherein said rim and airfoil regain said substantially planar shape in the presence of centrifugal force emanating from an axis perpendicular to the flight plane of said rim and airfoil.
 8. The device of claim 1, wherein said airfoil includes substantially non-air porous material.
 9. The device of claim 1, wherein said airfoil is formed from a molded material.
 10. The device of claim 1, wherein said outer rim is substantially annular in shape.
 11. The device of claim 1, wherein said airfoil includes an air porous material.
 12. A hand-thrown flying device, comprising: a non-tensed outer rim; and a flexible airfoil disposed at least in part within said rim and configured to permit air passage; wherein said airfoil is substantially planar in flight.
 13. The device of claim 12, wherein said airfoil defines a central opening.
 14. The device of claim 13, wherein said airfoil include a peripheral band disposed about said central opening that defines a plurality of peripherally disposed macroscopic air passage openings.
 15. The device of claim 12, wherein said airfoil includes substantially non-air porous material.
 16. A hand-thrown flying device, comprising: an outer rim; and a flexible airfoil disposed at least in part within said rim, wherein said rim and said airfoil are configured such that in flight said rim and said airfoil are planarly disposed in substantially the same plane; wherein said airfoil includes substantially non-air porous material.
 17. The device of claim 16, wherein said rim and airfoil are configured to be folded over and compressible in three mutually orthogonal directions, yet capable of being readily unfolded to regain a substantially planar shape.
 18. The device of claim 16, wherein said airfoil defines a plurality of macroscopic air passage openings.
 19. The device of claim 16, wherein said airfoil defines a central opening.
 20. The device of claim 16, wherein said airfoil defines a plurality of macroscopic peripherally disposed air passage openings.
 21. The device of claim 16, wherein said outer rim is substantially annular in shape.
 22. A hand-thrown flying device, comprising: a flexible, non-tensed airfoil having a top surface and a bottom surface that is disposed in a substantially planar shape in flight and configured to permit air passage between said top surface and said bottom surface.
 23. The device of claim 22, wherein said rim and airfoil are configured to be folded over and compressible in three mutually orthogonal directions, yet capable of being readily unfolded to regain a substantially planar shape.
 24. The device of claim 22, wherein said airfoil defines a central opening.
 25. The device of claim 22, wherein said airfoil defines a plurality of macroscopic peripherally disposed air passage openings.
 26. The device of claim 22, wherein said airfoil includes substantially non-air porous material.
 27. The device of claim 22, further comprising a non-tensed outer rim to which said airfoil is coupled.
 28. A hand-thrown flying device, comprising: a flexible airfoil that is capable of being disposed in a substantially planar shape and that defines a plurality of macroscopic air passage openings.
 29. The device of claim 28, wherein said airfoil includes substantially non-air porous material.
 30. The device of claim 28, further comprising an outer rim to which said airfoil is coupled. 